In GR as well as theories of modified gravity, wormholes are a set of solutions to the EFE just
like black holes and gravitational waves. The question of their traversability and whether they allow the existence of closed time-like curves facilitating both
backward and forward travel in time, is a question that requires further investigation. Wormholes composed of ordinary matter in the context
of GR are found to be unstable as the structure pinches off at the throat region due to gravitational collapse. However,
as suggested by Morris and Thorne[1]} three decades ago, if the throat contains matter which violates the NEC, then the pinch-off
can be prevented making the wormhole traversable. Such matter is called exotic matter. However, if we are to consider wormholes as solutions to the modified Einstein Field Equations (EFEs) in theories of modified gravity, then there is ususally no need for the wormhole to be supported by exotic matter as the modified geometry provides an “effective matter" description which causes the effective energy density and pressures to violate the NEC [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}, [11]}.
